The Center's goal is to lessen the toll that peptic ulcer diseases now exact in deaths, sickness and dollars. Through interdisciplinary studies on cells, tissues, animals man, and populations we expect to gain new insights into the causes and natural history of these diseases and to apply this knowledge to making improvements in the diagnosis, medical and surgical treatment, and prevention of these diseases. The 10 Key Investigators of the Center have expertise in one or more of these disciplines: biophysics, physiology, biochemistry, genetics, immunologg, endocrinology, gastroenterology, radiology, endoscopy, surgery, psychiatry, systems analysis and operations research, and epidemiology. Through an integrated program that will foster cross-disciplinary investigation, peptic ulcer will be studied at many levels. Examples of fields of study include: movement of hydrogen ions across normal and diseased gastroduodenal mucosae; mechanisms of abnormal secretion, motility, and mucosal growth in patients with peptic ulcer diseases; pathogenesis and treatment of acute diffuse hemorrhagic lesions of the stomach and duodenum; psychosomatic factors in causation and recurrence of peptic ulcer diseases; evaluation of standard and novel treatments for peptic ulcer diseases; assessment of optimal strategies for diagnosis and treatment of peptic ulcer diseases; use of serum pepsinogen and pepsinogen phenotype as diagnostic and prognostic tools; study og the amounts and kinds of gastrins in blood and tissues of controls and ulcer subjects; study of defined populations over long periods to determine prevalence and incidence of peptic ulcer diseases and their complications and to identify demographic, environmental, and genetic risk factors associated with occurrence and recurrence of peptic ulcer diseases.